Generalized Elliott-Yafet theory of electron spin relaxation in metals: origin of the anomalous electron spin lifetime in MgB2

• Published in: Physical review letters Vol. 101; no. 17; p. 177003
• Main Authors: Simon, F, Dóra, B, Murányi, F, Jánossy, A, Garaj, S, Forró, L, Bud'ko, S, Petrovic, C, Canfield, P C
• Format: Journal Article
• Language: English
• Published: United States 24-10-2008
• ISSN: 0031-9007
• DOI: 10.1103/PhysRevLett.101.177003

The temperature dependence of the electron-spin relaxation time in MgB2 is anomalous as it does not follow the resistivity above 150 K; it has a maximum around 400 K and decreases for higher temperatures. This violates the well established Elliot-Yafet theory of spin relaxation in metals. The anomaly occurs when the quasiparticle scattering rate (in energy units) is comparable to the energy difference between the conduction and a neighboring bands. The anomalous behavior is related to the unique band structure of MgB2 and the large electron-phonon coupling. The saturating spin relaxation is the spin transport analogue of the Ioffe-Regel criterion of electron transport.